From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C87B8C388F9 for ; Tue, 27 Oct 2020 14:43:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6F06F21527 for ; Tue, 27 Oct 2020 14:43:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603809795; bh=y0GFApQjWZe2gHBjOjdI0yRNIDYlQa3AZzDzTjZdvoA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=l6b5eS7gfSnzh2FbDS1mmIcLm8HOAi3l+GuW1PyXcFMC1Xb+uM96XjCgradF2aQQi SJQN4K3woQLNKpnuQB17mGudp9CHMtsZnsIdOAKp3cF6REbAxH9fGlmz+Nl47n20pc UKBJFdp1kUNSp8HLZxqHaWA1OWEiZ3WainrS5GyY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2899410AbgJ0OnO (ORCPT ); Tue, 27 Oct 2020 10:43:14 -0400 Received: from mail.kernel.org ([198.145.29.99]:39438 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761725AbgJ0OkO (ORCPT ); Tue, 27 Oct 2020 10:40:14 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 8EF4120773; Tue, 27 Oct 2020 14:40:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603809614; bh=y0GFApQjWZe2gHBjOjdI0yRNIDYlQa3AZzDzTjZdvoA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=vDBeBir/X32T91M5PRG6rASIvXUNa5Scsk8fD5XhmyydG9QpDrOP4aJUX7ayIfhHJ SBpdiOm1nbTSaUdfZM9lOO1SlTgHKPkDUAKTdhfgQdj+eCS9wTV7ynze2ZHrr4u75u xxzQwl5roS2t0wmH7Uw1hFmj0L0rj/YkyRXuUWIc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Da Xue , Sudeep Holla , Jerome Brunet , Jassi Brar , Sasha Levin Subject: [PATCH 5.4 259/408] mailbox: avoid timer start from callback Date: Tue, 27 Oct 2020 14:53:17 +0100 Message-Id: <20201027135507.056604428@linuxfoundation.org> X-Mailer: git-send-email 2.29.1 In-Reply-To: <20201027135455.027547757@linuxfoundation.org> References: <20201027135455.027547757@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jassi Brar [ Upstream commit c7dacf5b0f32957b24ef29df1207dc2cd8307743 ] If the txdone is done by polling, it is possible for msg_submit() to start the timer while txdone_hrtimer() callback is running. If the timer needs recheduling, it could already be enqueued by the time hrtimer_forward_now() is called, leading hrtimer to loudly complain. WARNING: CPU: 3 PID: 74 at kernel/time/hrtimer.c:932 hrtimer_forward+0xc4/0x110 CPU: 3 PID: 74 Comm: kworker/u8:1 Not tainted 5.9.0-rc2-00236-gd3520067d01c-dirty #5 Hardware name: Libre Computer AML-S805X-AC (DT) Workqueue: events_freezable_power_ thermal_zone_device_check pstate: 20000085 (nzCv daIf -PAN -UAO BTYPE=--) pc : hrtimer_forward+0xc4/0x110 lr : txdone_hrtimer+0xf8/0x118 [...] This can be fixed by not starting the timer from the callback path. Which requires the timer reloading as long as any message is queued on the channel, and not just when current tx is not done yet. Fixes: 0cc67945ea59 ("mailbox: switch to hrtimer for tx_complete polling") Reported-by: Da Xue Reviewed-by: Sudeep Holla Tested-by: Sudeep Holla Acked-by: Jerome Brunet Tested-by: Jerome Brunet Signed-off-by: Jassi Brar Signed-off-by: Sasha Levin --- drivers/mailbox/mailbox.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c index 0b821a5b2db84..3e7d4b20ab34f 100644 --- a/drivers/mailbox/mailbox.c +++ b/drivers/mailbox/mailbox.c @@ -82,9 +82,12 @@ static void msg_submit(struct mbox_chan *chan) exit: spin_unlock_irqrestore(&chan->lock, flags); - if (!err && (chan->txdone_method & TXDONE_BY_POLL)) - /* kick start the timer immediately to avoid delays */ - hrtimer_start(&chan->mbox->poll_hrt, 0, HRTIMER_MODE_REL); + /* kick start the timer immediately to avoid delays */ + if (!err && (chan->txdone_method & TXDONE_BY_POLL)) { + /* but only if not already active */ + if (!hrtimer_active(&chan->mbox->poll_hrt)) + hrtimer_start(&chan->mbox->poll_hrt, 0, HRTIMER_MODE_REL); + } } static void tx_tick(struct mbox_chan *chan, int r) @@ -122,11 +125,10 @@ static enum hrtimer_restart txdone_hrtimer(struct hrtimer *hrtimer) struct mbox_chan *chan = &mbox->chans[i]; if (chan->active_req && chan->cl) { + resched = true; txdone = chan->mbox->ops->last_tx_done(chan); if (txdone) tx_tick(chan, 0); - else - resched = true; } } -- 2.25.1